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Biomedical subjects

A Ekman

Publications and source records attributed to A Ekman.

At least 19 recordsLinked to original sources
PubMed2004

Reduction in the incidence of awareness using BIS monitoring.

BACKGROUND: Explicit recall (ER) is evident in approximately 0.2% of patients given general anaesthesia including muscle relaxants. This prospective study was performed to evaluate if cerebral monitoring using BIS to guide the conduction of anaesthesia could reduce this incidence significantly. PATIENTS AND METHODS: A prospective cohort of 4945 consecutive surgical patients requiring muscle relaxants and/or intubation were monitored with BIS and subsequently interviewed for ER on three occasions. BIS values between 40 and 60 were recommended. The results from the BIS-monitored group of patients was compared with a historical group of 7826 similar cases in a previous study when no cerebral monitoring was used. RESULTS: Two patients in the BIS-monitored group, 0.04%, had ER as compared with 0.18% in the control group (P < 0.038). Both BIS-monitored patients with ER were aware during intubation when they had high BIS values (> 60) for 4 min and more than 10 min, respectively. However, periods with high BIS = 4 min were also evident in other patients with no ER. Episodes with high BIS, 4 min or more, were found in 19% of the monitored patients during induction, and in 8% of cases during maintenance. CONCLUSIONS: The use of BIS monitoring during general anaesthesia requiring endotracheal intubation and/or muscle relaxants was associated with a significantly reduced incidence of awareness as compared with a historical control population.

Adolescent↗
PubMed2004

A comparison of bispectral index and rapidly extracted auditory evoked potentials index responses to noxious stimulation during sevoflurane anesthesia.

In 21 patients given sevoflurane anesthesia, we simultaneously compared the abilities of Bispectral Index (BIS) and rapidly extracted auditory evoked potentials index (AAI) to display the effect of an increasing cerebral concentration of sevoflurane, with and without noxious stimulation. In addition to BIS/AAI, hemodynamic variables were monitored. After titrating sevoflurane to BIS = 50-55 during 15 min, the end-tidal concentration of sevoflurane (1.46% +/- 0.20%) was doubled followed by a noxious stimulus, laryngoscopy, applied at random time points within the following 15 min. After the end-tidal concentration of sevoflurane was doubled, a substantial reduction in BIS was observed, whereas only a slight reduction in AAI was seen (P < 0.0001). BIS/AAI responses to laryngoscopy were not attenuated with increasing wash-in of sevoflurane. After noxious stimulation, AAI exceeded the highest recommended value, 25, in 3 cases, whereas BIS did not exceed the recommended threshold, 60, in any of the patients. Response times for BIS and AAI were 44.5 +/- 26 and 47 +/- 31 s, respectively. These results suggest that, at a hypnotic level associated with surgical sevoflurane anesthesia, BIS better displays drug-related alterations in the level of hypnosis than AAI or hemodynamic variables but there is no difference between BIS and AAI in the time to response to a noxious stimulus.

Adult↗
PubMed2003

Serotonin transporter gene polymorphisms and platelet [3H] paroxetine binding in premenstrual dysphoria.

The purpose of this study was to investigate if women with premenstrual dysphoria differ from controls with respect to the number of platelet serotonin transporters, and with respect to three polymorphisms in the gene coding for the serotonin transporter: a 44 base pair insertion/deletion in the promoter region, a variable number of tandem repeats in the second intron, and a single nucleotide polymorphism in the 3' untranslated region. Also, the possible relationship between the three polymorphisms and platelet serotonin transporter density was analyzed. The density of platelet [(3)H]paroxetine binding sites was significantly lower in women with premenstrual dysphoria than in controls, but patients and controls did not differ with respect to allele or genotype frequency for any of the three polymorphisms examined. A significant association between the number of platelet serotonin transporters and the promoter polymorphism was observed, subjects being homozygous for the short (deletion) variant having higher platelet serotonin transporter density than subjects carrying the long (insertion) allele. The results support the assumption that serotonin-related psychiatric disorders-such as premenstrual dysphoria-may be associated with a reduction in platelet [(3)H]paroxetine binding, but argue against the notion that this reduction is due to certain variants of the serotonin transporter gene being more common in patients than in controls.

Adolescent↗
PubMed2001

DXA of the hip and heel ultrasound but not densitometry of the fingers can discriminate female hip fracture patients from controls: a comparison between four different methods.

Dual-energy X-ray absorptiometry (DXA) of the proximal femur and in more recent years quantitative ultrasound (QUS) of the heel are the most established methods for assessing hip fracture risk. Measurement of the fingers offers a new approach. We performed DXA of the proximal femur, QUS of the heel and fingers, and radiographic absorptiometry (RA) of the fingers in 87 non-institutionalized women, 65-85 years of age, with a first hip fracture and compared them with 195 randomly selected age-matched controls. Bone mineral density (BMD) of the femoral neck and heel Stiffness Index were significantly lower among cases than among controls (by 15% and 17%, respectively; p < 0.0001), whereas no significant differences were found for finger measurements. When applying the WHO criterion of osteoporosis, 62-98% of the patients were classified as osteoporotic, compared with 19-85% of the controls, depending on method and site. The risks of hip fracture, estimated as odds ratios for every 1 SD reduction in femoral neck BMD, heel Stiffness Index, finger QUS and finger RA, were: 3.6 (95% CI 2.4-5.5), 3.4 (95% CI 2.2-5.0), 1.0 (95% CI 0.7-1.3) and 1.2 (95% CI 0.8-1.6), respectively. Compared with women with normal BMD of the femoral neck, those classified as osteopenic had an odds ratio of hip fracture of 14 (95% CI 2-110), whereas those classified as osteoporotic had an odds ratio of 63 (95% CI 8-501). We conclude that hip DXA and heel QUS have similar capacities to discriminate the risk of a first hip fracture, whereas QUS and RA of the phalanges seem inferior techniques for differentiating female hip fracture patients from controls.

Absorptiometry, Photon↗
PubMed2001

Almost all institutionalized women are osteoporotic, when measured by heel and finger ultrasound.

OBJECTIVES: Since there is a need for simple methods to identify individuals with osteoporosis, we investigated bone status (heel and finger) with ultrasound in an institutionalized elderly population and studied the association between these measures, risk factors for osteoporosis and prevalent osteoporotic fractures. DESIGN: Cross-sectional study. Subjects. Nursing home residents, 237 women and 84 men, mean age 84 years. RESULTS: Altogether 82% of those eligible could undergo heel ultrasound, 65% finger ultrasound and 41% measurements at both sites. Using a transcription of the WHO criterion of osteoporosis, 95% of the women who underwent heel ultrasound were classified as osteoporotic (mean T-score = -4.8) and 92% had Z-scores below zero (mean Z-score=-1.6), whereas 51% of the men were osteoporotic (mean T-score=-2.6) and 77% had Z-scores below zero (mean Z-score=-1.3). Based on finger ultrasound measurements, 99% of the women were classified as osteoporotic (mean T-score=-5.0) and 93% had Z-scores below zero (mean -1.6). The variations in ultrasound values were only moderately explained by age, current weight and walking ability. Amongst women, the association with a prevalent osteoporotic fracture decreased by 43% (95% CI=10-63%) for every SD increase in speed of sound (SOS) of the heel, but no such relationship was found for finger SOS. CONCLUSIONS: Our results from ultrasound measurements at two different anatomical sites indicate that virtually all institutionalized elderly women could be classified as osteoporotic, when measured by these techniques.

Aged↗
PubMed2001

Increased nitric oxide in exhaled air after intake of a nitrate-rich meal.

Exhaled and nasal NO (ENO, NNO) have been suggested as markers for inflammation in lower and upper respiratory tract respectively. It is still unknown how a number of factors, apart from airway inflammation, can influence NO levels. The aim of this study was to determine the effect of a nitrate-rich meal on ENO and NNO. Sixteen healthy subjects were observed during 1 week on normal diet before a nitrate-restricted diet was introduced in the next. On day 3 of the second week they were made to ingest a nitrate rich meal. ENO, NNO, plasma nitrate and plasma L-arginine were followed before the meal and afterwards for 3 h. ENO and NNO as well as plasma nitrate and plasma L-arginine were significantly elevated after the nitrate-rich meal. The median maximal increase of ENO and NNO was 47% and 13% respectively. We found a moderate but significant correlation between the rise in plasma nitrate and ENO (r(s)=0.57, P=0.027) but none between plasma nitrate and NNO (r(s)=-0.02, P=0.95). As nitrate in the diet seems to substantially influence the levels of ENO it is important either to restrict or register the intake of nitrate-rich food prior to measuring ENO.

Adult↗
PubMed2001

Nitric oxide (NO) in exhaled air after experimental ozone exposure in humans.

We hypothesized that ozone, a common air pollutant, potent in producing airway inflammation, would increase the production of exhaled nitric oxide (NO). If so, measurement of exhaled NO could potentially be a valuable tool in population studies of air pollution effects. Eleven healthy non-smoking volunteers were exposed to 0.2 ppm ozone (O3) and filtered air for 2h on two separate occasions. Exhaled NO and nasal NO were measured before and on five occasions following the exposures. Changes in exhaled and nasal NO after ozone exposure were adjusted for changes after air exposure. There was a slight decrease in exhaled NO (-0.6; -3.1-1.2 ppb) (median and 95% confidence interval) and of nasal NO (-57; -173-75 ppb) directly after the ozone exposure. No significant changes in exhaled or nasal NO were however found 6 or 24 h after the exposure. Within the examined group, an O3 exposure level proven to induce an airway inflammation caused no significant changes in exhaled or nasal NO levels. Hence, the current study did not yield support for exhaled NO as a useful marker of ozone-induced oxidative stress and airway inflammation after a single exposure. This contrasts with data for workers exposed to repeated high peaks of ozone. The potential for exhaled NO as a marker of oxidative stress therefore deserves to be further elucidated.

Adult↗
PubMed2000

Distributions of Li+, Na+ K+, Rb+, and Cs+ tracer ions in erythrocytes at 38 degrees C in relation to entry rates of these ions into cells at 0 degree C.

Forces that are able to transport Na+ and K+ into two compartments were investigated. A modified Nernst-Planck equation for coupled flows of electric current, water, and ions was integrated. The result shows that if alkali ions in the ion channel of the cell membrane are separated by their electric-current-induced inward flows against an electro-osmotic outward flow of water, the logarithms of the stationary cell/medium distributions of these ions should be proportional to the inverse of their diffusion mobilities. The relationship was tested in human erythrocytes. From inward and outward movements of tracer alkali ions, calculations were made to obtain their stationary distributions at infinite time. The cell/medium distributions determined in this way at 38 degrees C are Li+ = 0.59, 22Na+ = 0.044, 42K+ = 10.0, 86Rb+ = 11.9, and 137Cs+ = 3.07. The entry rates of ions into the cell at 0 degrees C are understood to represent their diffusion mobilities in the pump channel. The entry rates are Li+ = 1.44, 2Na+ = 1, 42K+ = 2.22, 86Rb+ = 2.39, and 137Cs+ = 1.72 relative to that of 22Na+. There is an expected negative correlation between the logarithms of the stationary cell/ medium distributions at 38 degrees C and the inverse of the entry rates into the cell at 0 degrees C for the five ions. It is suggested that the proposed physical forces cause the separation of alkali ions in the channel of Na,K-ATPase.

Biological Transport, Active↗
PubMed2000

Gender differences in musculoskeletal health of computer and mouse users in the Swedish workforce.

The objectives of the study were to explore the musculoskeletal health of computer users in the Swedish workforce with regard to gender and psychosocial factors, and to describe gender differences between the occupational groups. A subset was chosen from a large survey of 12,462 individuals representing the workforce of Sweden, performed by Statistics Sweden. Included in the subset were 2044 subjects who worked for at least half their working hours with personal computers, or an equivalent device, and also used a computer mouse. All occupational groups had prevalence ratios (women/men) > 1. When using regression models, the variables 'learn and develop' and 'involved in planning your work' were health factors, and 'too much to do' was a risk factor for upper body symptoms for both women and men. For women 'PC duration 100' was a risk factor and 'support from superiors' was a health factor. Age seemed to be a stronger risk factor for men than for women.

Adult↗
PubMed1999

Both dopamine and the putative dopamine D3 receptor antagonist PNU-99194A induce a biphasic inhibition of phorbol ester-stimulated arachidonic acid release from CHO cells transfected with the dopamine D3 receptor.

In Chinese hamster ovary (CHO) cells transfected with the cDNA for the dopamine D3 receptor, low concentrations of dopamine (IC50: 0.5 nM) counteracted the release of arachidonic acid (AA) induced by the protein kinase C activator TPA (maximal inhibition: 15% at 10 - 30 nM). The effect of dopamine -- which was antagonized by pretreatment with pertussis toxin (PTX) or by the dopamine receptor antagonist haloperidol -- was biphasic; thus, at increasing concentrations of dopamine (100 nM - 1 microM), AA levels approached baseline. The preferential dopamine D3 receptor ligand PNU-99194A displayed an effect similar to that of dopamine; thus, whereas low concentrations of PNU-99194A (IC50: 1.9 nM) reduced TPA-induced AA release (maximal inhibition: 15% at 30 - 100 nM), higher concentrations (> or =1 microM) were ineffective. When dopamine and PNU-99194A were administered together at concentrations yielding maximal inhibition of AA release, no additive effect was observed; moreover, a high concentration of dopamine counteracted the AA-reducing effect of a low concentration of PNU-99194A and vice versa. It is suggested that D3 receptors in transfected CHO cells may exert mainly an inhibitory, but also a stimulatory influence on TPA-induced AA release, and that PNU-99194A acts as an agonist in this system.

Animals↗
PubMed1998

Insensitivity of the routine dimethylglyoxime test for detecting release of nickel from earrings.

The Helsinki City Centre of the Environment tested two methods, dimethylglyoxime (DMG) and atomic absorption spectrometry (AAS), for detecting nickel release in piercing earrings. The DMG screening test was performed in two slightly different ways, with and without ethanol and heat prehandling. All 30 pairs of earrings tested, totalling 66 objects, were negative. However, according to our AAS test, 25 of the 66 objects (38%) released > or = 0.05% of nickel, the mean amount being 2.1% and the maximum 12%. When measured by AAS after artificial sweat treatment, 11 objects released more than 0.5 microgram/cm2 per week of nickel, the mean amount being 3.4 micrograms/cm2 and the range < 0.1-84 micrograms/cm2. After this sweat treatment, nine of the objects (14%) were positive in DMG tests. These findings indicate that the DMG test is unreliable for detecting nickel release from jewelry. Quality control of consumer items should be performed by laboratories that have quantitative analysis methods for such investigations.

Chemistry Techniques, Analytical↗
PubMed1998

Central administration of dopamine D3 receptor antisense to rat: effects on locomotion, dopamine release and [3H]spiperone binding.

A 15-mer, all-phosphorothioate-modified antisense oligodeoxynucleotide (ASO) targeted against rat dopamine D3 receptor mRNA (4 microM, 5 days) significantly reduced (28%) the amount of binding sites labelled with [3H]spiperone in monolayer cultured Chinese hamster ovary (CHO) cells transfected with the complementary desoxyribonucleic acid (cDNA) for the rat D3 receptor. In contrast, D3-ASO treatment did not reduce the amount of bound [3H]spiperone in CHO cells transfected with D2 receptor cDNA. Intracerebroventricular infusion of D3-ASO (osmotic minipump, 10 microg/microl/h, 7 days) influenced dopamine receptor density in the limbic forebrain such that the upper part of the dopamine/[3H]spiperone displacement curve--tentatively representing the D3 receptor--was altered significantly. Spontaneous locomotor activity of non-habituated rats was increased significantly in D3-ASO-treated animals; in addition, in vivo microdialysis revealed a moderate increase in dopamine release in the nucleus accumbens in these animals. In all experiments, an oligodeoxynucleotide comprising the same nucleotides as the antisense sequence, but in random order, was used as control. It is concluded that the antisense strategy is useful for investigating the functional role of dopamine D3 receptors and that the dopamine D3 receptor is involved in rat locomotor behaviour.

Animals↗
PubMed1998

The intrinsic activity of (-)-3-PPP vis-à-vis prolactin-suppressing dopamine D2 receptors in transfected GH4C1 cells is dependent on which secretagogue that is used to provoke prolactin release.

The abilities of dopamine (DA) and the partial DA D2 receptor agonist (-)-(3-hydroxyphenyl)-N-n-propylpiperidine, (-)-3-PPP, to suppress prolactin (PRL) release induced by any of five different PRL secretagogues in GH4C1 cells transfected with the human D2 receptor (short isoform) were investigated. Whereas DA reduced the response to all five secretagogues. (-)-3-PPP reduced the response to vasoactive intestinal peptide (VIP) and thyrotropin-releasing hormone (TRH), but not to high medium potassium (K+) or to the potassium channel antagonist tetraethylammonium (TEA). (-)-3-PPP tended to reduce the PRL release induced by the Ca2+ channel agonist BAY K-8644 (BAY); however, this effect of the partial agonist was modest and not significant. Whereas the effects of both DA and (-)-3-PPP on the PRL response to VIP and TRH were counteracted by co-incubation with the D2 antagonist raclopride, the effects of DA on the PRL response to K+, BAY, and TEA were antagonized by co-incubation with either raclopride or (-)-3-PPP. The results show that, at a given receptor density, the intrinsic activity of a partial D2 agonist with respect to D2-mediated suppression of PRL release may vary from agonism to antagonism depending on which intracellular transduction systems that are being concomitantly activated.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

Direct dopamine D2-receptor-mediated modulation of arachidonic acid release in transfected CHO cells without the concomitant administration of a Ca2+-mobilizing agent.

In CHO cells transfected with the rat dopamine D2 receptor (long isoform), administration of dopamine per se elicited a concentration-dependent increase in arachidonic acid (AA) release. The maximal effect was 197% of controls (EC50=25 nM). The partial D2 receptor agonist, (-)-(3-hydroxyphenyl)-N-n-propylpiperidine [(-)-3-PPP], also induced AA release, but with somewhat lower efficacy (maximal effect: 165%; EC50=91 nM). The AA-releasing effect of dopamine was counteracted by pertussis toxin, by the inhibitor of intracellular Ca2+ release, 8-(N N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), by excluding calcium from the medium, by the phospholipase A2 (PLA2) inhibitor, quinacrine, and by long-term pretreatment with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). In addition, it was antagonized by the D2 antagonists, raclopride and (-)-sulpiride--but not by (+)-sulpiride--and absent in sham-transfected CHO cells devoid of D2 receptors. The results obtained contrast to the previous notion that dopamine and other D2 receptor agonists require the concomitant administration of calcium-mobilizing agents such as ATP, ionophore A-23187 (calcimycin), thrombin, and TRH, to influence AA release from various cell lines.

Adenosine Triphosphate↗
PubMed1996

Differential effects of tumor necrosis factor and asbestos fibers on manganese superoxide dismutase induction and oxidant-induced cytotoxicity in human mesothelial cells.

We compared induction of manganese superoxide dismutase (MnSOD) by asbestos fibers and tumor necrosis factor alpha (TNF) using cultured human mesothelial cells. Transformed pleural mesothelial cells (MET 5A) were exposed for 48 h to amosite asbestos fibers (2 micrograms/cm2), to TNF (10 ng/ml), and to the combination of these two. TNF and amosite+TNF caused significant MnSOD mRNA upregulation. Similarly MnSOD specific activity was increased by TNF (290% increase) and the amosite+TNF combination (313% increase) but not by amosite alone. In cell injury experiments, amosite and amosite+TNF exposures caused significant cell membrane injury when assessed by lactate dehydrogenase release, which was 31% and 57% higher than in the unexposed cells. However, only the amosite+TNF combination caused significant depletion of cellular high-energy nucleotide when expressed as percentage of [14C]adenine labeling in cellular high-energy nucleotides. The nucleotide levels were 91.5 +/- 2.0% in the unexposed cells, 89.9 +/- 3.9% in amosite-exposed cells, 90.1 +/- 2.2% in TNF-exposed cells, and 79.8 +/- 9.4% in amosite+TNF-exposed cells. Amosite+TNF-exposed cells were also most sensitive to menadione (20 mumol/L, 2 h), a compound which generates superoxide radicals intracellularly. In conclusion, our data suggests that in human mesothelial cells inflammatory cytokines but not asbestos fibers alone can cause MnSOD induction. In this study, however amosite asbestos+TNF treatment rendered these cells more vulnerable to oxidant-induced cell damage despite elevated MnSOD activity.

Asbestos, Amosite↗